1. Field of the Invention
The invention relates to position determining software. More specifically, the field of the invention is that of visual survey system software for enhancing the accuracy of visual survey systems in real time applications.
2. Description of the Related Art
The approaches described in this section could be pursued, but are not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, the approaches described in this section are not teachings or suggestions of the prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
There is increasing need for systems that can map transportation infrastructure to ever higher levels of accuracy. Highly accurate survey map data may be used for lane departure warning systems on highways, corridor clearance in transportation systems, and vehicle automation in general with particular application to detection of pavement surface difference for condition assessment and to automated roadway foreign object detection. As vehicular automation, robotic applications, and transportation electronic infrastructure evolve, further use of visual survey systems will be needed.
The purpose of a surveying system is to record the absolute position/orientation of objects that can be seen in imagery taken from survey vehicles. To do this, the survey vehicle must accurately record its own absolute position/orientation and it must be able to attain the relative position/orientation of the target object. It can then calculate the absolute position/orientation of the target object to within the combined errors of the absolute and relative systems.
To achieve this, the survey vehicle has several instruments designed to record the position and orientation of itself and the objects around it. The vehicle travels through the survey area capturing and recording the data from the sensors at specified time or distance intervals. That is, at particular moments, the cameras, GPS, INS, and other instruments capture their readings.
Once data is collected for the survey, it is used to extract information about the survey area. Objects visible in particular images can be located by correlating the capture point data to the image. Other information about the objects can be extracted such as sign types, road markings, centerlines, and other visible attributes.
However, known systems have measurement error because of the physical limitations of the survey systems. While accurate in many respects, there are situations where enhanced accuracy is desired.